Pistons



J. BURNAND Nov. 18, 1958 PISTONS 5 Sheets-Sheet 1 Filed Sept. 6, 1956FIG.I

firroknsra Nov. 18, 1958 J. BURNAND 2,860,614

PISTONS Filed Sept. 6, 1956 5 Sheets-Sheet 5 Nov. 18, 1958 J. BURNAND2,860,614

PISTONS Hm M N tmi United States Patent 2,860,614 PISTONS John Burnand,Teddington, England Application September 6, 1956, Serial No. 608,235 7Claims. (C1, 123-4138) This invention is concerned with improvements inor relating to pistons for internal combustion engines.

Features and advantages of the present invention will appear from thefollowing description of two embodiments of piston, given by way ofexample only, reference being made to the accompanying drawings inwhich:

Figure 1 is a longitudinal cross section of the piston,

Figure 2 is a longitudinal cross section of the piston on the line II-IIof Figure 1,

Figure 3 is a plan view of the lower bearing incorporated in the piston,

Figure 4 is an elevation of the lower bearing,

Figure 5 is aplan'vi'ew of the upper bearing,

Figure 6 is an elevation of the upper bearing and Figure 7 is a crosssection of another embodiment of piston.

The piston comprises a head 1 having an annular depending skirt 2,internally threaded as at 3, preferably with a buttress thread.

Within the piston fits a member 4 which forms a strut supporting theunderface of the piston head and which forms an upper bearing, as at 5for a gudgeon pin 6, which preferably is formed integrally with aconnecting rod 7.

The member 4 externally has the appearance somewhat of a piston, beingcircular to fit in the skirt 2, and having an annular skirt 8, thebearing surface 5 being formed in the under face of the head of themember 4. The skirt 8 is provided with diametrically opposed slots 9whereby the member 4 may be placed upon the gudgeon pin.

Also in the piston skirt 2 is a lower bearing comprising two lowerbearing pieces 10 each of which comprises a part 11 forming a saddlebearing for the lower face of an arm of the gudgeon pin, and a plate 12which is generally semi-circular, has a recess 13 in its straight edgeand is buttress threaded as at 1311. If desired the plate 12 may bereduced in volume by forming a skirt as at a Figure 4 depending from theplate 12 around its curved edge.

To assemble the piston the head may be placed upside down upon forexample a bench, the member 4 is placed in the head, the gudgeon pinwith its connecting rod is placed in position in the upper bearing, thelower bearings are held at the mouth of the piston skirt, the connectingrod extending through the aperture formed by the recesses 13 and thehead is rotated for example by rotating the connecting rod so that thelower bearing is drawn into the skirt. Any suitable means may be usedfor holding the lower bearing during rotation of the head. The lowerbearings are then looked in position by any suitable means.

The connecting rod has a central gallery 14 which leads to a passage 15in the gudgeon pin. From the passage 15 lead passages 16 which extend tothe upper surface of the gudgeon pin.

In the head of the member 4 are openings 17 and in the underface of thepiston head 1 are grooves 18. Oil or other suitable lubricant material,preferably having cooling, lubricating and detergent properties, ispassed up the connecting rod gallery 14 and moves out by the passages 15to the gudgeon pin upper surface, and through the member 4 to theunderface of the piston head thus cooling the head. If desired thedimensions of the passages 17 may be so selected 'in relation. to theangle of movement of the connecting rod and passages 16 that the flow oflubricant is intermittent to the head, the passages 16 being opened andclosed as they register and pass out of register with the passages 17.

Lubricant escapes from the underface of the piston head to an annularrecess 19 whence it passes by openings 20 to passages 21 in the skirt 2.From each passage 21 lead holes 22 project to the outer surface of theskirt. I at present prefer to provide one below a top recess 23 for apiston ring and one adjacent the bottom of the skirt 2. The passages 21are preferably blocked off at the ends as at 24, but it may be desirableto provide an adjustable opening to control the flow of lubricant to theouter surfaces of the piston skirt.

A channel 25 may be provided at the base of the cylinder bore to collectthe lubricant as it runs down the cylinder walls and as it leaves thepassages 21, whence it may be returned in any suitable way to thelubricant source.

Whilst I have described the strut as having an integral upper bearingsurface, it will be understood that in some cases a separate upperbearing surface may be preferred.

This piston is primarily intended for short stroke high speed enginesbut is of a construction applicable to other uses. The piston beingbuilt up of a number of interfitting parts, the danger of cracking isreduced and the top surface of the piston head is shown as having aparticular shape but it may be preferred in some cases to provide aflat, concave or other shaped top surface. Any suitable piston ring maybe employed. At present I prefer to provide a plurality of ringsadjacent the top of the piston, being compression rings, and to providea ring adjacent the base of the piston to act as a scraper to removeimpurities from the cylinder walls.

It will be seen that the connecting rod has an angular travel limitedonly by the rim of the piston skirt.

The lower bearing if desired may be made in the form of two plates, fromeach of which extends a part forming a saddle bearing, the two lowerbearings being held in place by a complete ring engaging the threads inthe piston skirt.

Referring now to Figure 7 there is shown in cross section a piston whichis of similar construction but in which no removable strut is provided.In this embodiment the piston comprises a somewhat thicker head on theunderface of which is a bearing recess 31 for gudgeon pin 32. Two lowerbearing pieces, only one, 33, of which is shown, are received by a skirt35 of the piston and abut the under side of the head. Channels 36 areformed in the upper bearing surface and. these communicate with channels37 formed in the underside of the head, channels 37 communicating withreturn passages 38 in the skirt as in the previously describedembodiment.

Instead of the head illustrated I may adopt the head illustrated inFigures 1 and 2 of my copending application No. 510,787 which includes athreaded ring for clamping piston rings against chatter and hencepreventing a pumping action by the rings tending to pump lubricant upinto the combustion chamber.

It will be seen that a piston may be provided of which the parts can bemade by automatically operating machinery and these parts may beassembled by machine.

I claim:

1. A piston comprising a solid head having a loadreceiving outsidesurface and an internal surface, parallel channels formed in saidinternal surface and extending over that surface, agudgeon pin upperbearing surface channels in said upper bearing surface communicatingwith said channels in said internal surface, removable gudgeon pin lowerbearing means and a lower bearing retaining member.

2. A piston comprising a solid head having a loadreceiving outsidesurface and an internal surface, channels formed in said internalsurface and extending over that surface, a gudgeon pin upper bearingsurface channels in said upper bearing surface communicating with saidchannels in said internal surface, removable gudgeon pin lower bearingmeans, a lower bearing retaining member and a gudgeon pin, oil galleriestherein communicating with the exterior of said gudgeon pin and thechannels in the gudgeon pin upper bearing surface.

3. A piston according to claim 1 in which at least one gallery isprovided in a skirt depending from said head, said gallery communicatingwith said channels in said internal surface.

- 4. A piston comprising a solid head having a loadreceiving outsidesurface and an internal surface, channels formed in said internalsurface and extending over that surface, a strut engaging said internalsurface, a gudgeon pin upper bearing surface associated with theunderface of said strut, channels in said upper bearing surface andextending through the strut to that face abutting said internal surfaceof said head, removable gudgeon pin lower bearing means and a lowerbearing retaining member.

5. A piston comprising a solid head having a loadreceiving outsidesurface and an internal surface, channels joined in said internalsurface and extending over that surface, a strut engaging said internalsurface, a gudgeon pin upper bearing surface associated with theunderface of said strut, channels in said upper bearing surface andextending through the strut to that face-abutting said internal surfaceof said head, removable gudgeon pin lower bearing means, a lower bearingretaining member, and a gudgeon pin, oil galleries therein communicatingwith the exterior of said gudgeon pin and the channels in the gudgeonpin upper bearing surface.

6. A piston according to claim 4 in which at least one gallery isprovided in a skirt depending from said gallery communicating with saidchannels in said internal surface.

7. A piston comprising a solid head having a load receiving outsidesurface and an internal surface, said internal surface defining agudgeon pin upper'bearing surface, channels formed in said internalsurface and in said upper bearing surface said channels insaid surfacesbeing in communication with removable gudgeon pin lower bearing meansand a lower bearing retaining member.

References Cited in the file of this patent v UNITED STATES PATENTS

